I don't think it's about the standard. It's about Qualcomm making most modems and about who owns Qualcomm. The US government worries that 90% of the modems will be produced by China (Broadcom/Qualcomm + Huawei + ZTE).

I think this should absolutely be a concern for US national security. But I also think there's something they're not telling us here. A lot of this sounds like the US government may already have its own backdoors in Qualcomm modems, and they don't want to give that up.

Whether that's real or not, the #1 concern is still that China would be able to backdoor any wireless equipment in the US from factory.

I don't see any reason why that shouldn't be taken seriously, especially when China requires by law backdoors in Chinese products and services.